Conveying drying apparatus



ANov. [2, 1957 H. w. HAPMAN CONVEYING DRYING APPARATUS Filed May 19, 1952 3 Sheets-Sheet 1 Nov. 12, 1957 H. w. HAPMAN CONVEYING DRYING APPARATUS Filed May 19, 1952 5 Sheets-Sheet 2 IIIIIIIII/I/A (ttorneg 5 Nov. l2, 1957 H. w. HAPMAN CONVEYING DRYING APPARATUS 3 Sheets-Sheet 3 iled May 19, 1952 nited States Patent() CONVEYING DRYING APPARATUS Henry W. Hapman, Hickory Comcrs, Mich., assignor of forty percent to Hannah Jane Hapman, Hickory Corners, Mich.; Melvin S. Hulfakcr and Hannah Jane Hapman, executors of said Henry W. Hapman, deceased Application May 19, 1952, Serial No. 288,736

2 Claims. (Cl. 257-23) This invention relates to drying apparatus and, in particular, to such apparatus Where the material is conveyed while being dried, refrigerated, or otherwise heattreated.

One object of this invention is to provide a conveying dryer which will dry a greater thickness of material While conveying it than it is possible to dry with the socalled drum dryer, which will dry only that thickness -of material which adheres to the rotating drum.

can be subjected to the application of gaseous or vapor A pressure during the drying operation without the escape of such pressure from the drying chamber.

Another object is to provide a conveying dryer which will occupy a much smaller space, have less weight and be much less expensive to manufacture than a Couventional rotating drum dryer for an equal drying capacity.

Another object is to provide a conveying dryer Wherein the material to be dried is conveyed over an elongated flat table and subjected to the action of a series of elongated wiper blades of resilient material, such 'as spring steel mounted on endless conveyor chains so as -to scrape the plate clean of material.

Another object is to provide a conveying dryer of the foregoing character which operates continuously under atmospheric conditions or under either pressurized or vacuum conditions, the dried material being carried away through an auxiliary conveyor and fresh material supplied to the drying chamber through another auxiliary conveyor.

Another object is to provide a modified at plate dryer wherein the discharge end of the dryer can be raised and lowered so that when it is raised liquid can be retained in greater quantity at the opposite end of the dryer. Another object is to provide a modified conveying dryer wherein the material is conveyed by an endless -metal belt of steel or other suitable metal while the belt isbeing heated to accelerate the drying operation, the

heat being preferably applied beneath the belt, this modified dryer being well adapted for the drying of materials which pass through a sticky state before becoming a dry powder.

Other objects and advantages of the invention will become apparent during the course of the following description of the accompanying drawings, wherein:

VFigure 1 is a side elevation of a ilat plate dryer, with one Side 'ofthe' 'housing' "broken away, and employing 2,812,924 Patented Nov. 12, '1957 ICC an endless conveyor with Scrapers, according to one form of the invention, shown as optionally equipped for pressurized or vacuum operation;

Figure 2 is a cross-section taken along the line 2-2 in Figure 1;

Figure 3 is a vertically-inclined section through the auxiliary discharge conveyor taken along the line 3-.3 in Figure l;

Figure 4 is a fragmentary enlarged end elevation of one of the Scrapers attached to the endless conveyor chain; Y 1

Figure 5 is a fragmentary top plan view of the portion of the scraper and conveyor chain shown in Figure 4;

Figure 6 is a fragmentary vertical cross-section taken along the line 6-6 in Figure 4;

Figure 7 is a side elevation of a modification of the flat plate dryer shown in Figure 1, wherein the discharge end of the dryer can be raised or lowered;

Figure 8 is a top plan View of a further modicatio of the conveying dryer shown in Figure l on a reduced scale, wherein the intake and discharge ends are provided with pressure-sealing devices;

Figure 9 is a right-hand end elevation of the conveying dryer shown in Figure 8 at the discharge end thereof;

Figure l0 is a left-hand end elevation of the conveying dryer shown in Figures 8 and 9 at the intake end thereof;

Figure l1 is a central longitudinal section through a still further modification of the conveying dryer of Figure 1, wherein the material is conveyed by an endless flexible metal belt and dried by heat applied to the belt;

Figure 12 is a cross-section taken along the line 12-12 in Figure l1; and

Figure 13 is a fragmentary enlarged end elevation of a modified scraper attached to the endless conveyor chain.

Flat plate dryer with endless conveyor and Scrapers Referring to the drawings in detail, Figures l to 6 inclusive show one form of conveying dryer, generally designated 20, according to one form of the invention as having a box-like elongated housing 21 supported upon legs 22 of angle or channel steel and equipped with a sloping roof orvcover 23. The roof 23 is equipped with an inclined bulk feed intake conduit 24 at the intake end thereof, likewise a liquid feed conduit 2,5 and an air inlet conduit 26. A bulk feed intake opening or port 27 for the conduit 24 is also provided in vthe intake end wall 28 of the housing 21, and the air inlet conduit 26 is connected to a port 31 in the same Wall 28. Mounted on the roof 23 of the housing 21 near the discharge end wall 29 thereof is a vapor vent stack or conduit 30. The casing 21 is provided with air inlet and outlet conduits 32 and 32a leading into the lower portions thereof. Journaled in bearing boxes 33 and 34 (Figure 2) in the opposite sides 35 of the housing 21 is a shaft 37 carrying a pair of idler sprockets 3 8 with endless chains 39. Secured Vto the sprocket chains 39 at intervals therealong are angle brackets 40 y (Figure 6) to which in turn are bolted or otherwise secured channel members 41 (Figure 4). Secured to the underside of each channel member 41 as by the bolt 42 is an elongated Wiper blade or scraper V43 of resilient material, such as spring steel, and of approximately channel cross-section with oppositely-inclined scraping llanges or sides 44 and 45, the Scrapers 43 being an chored in position by bars 46.

Also secured as at 47 to the side lianges of the channels 41 are corner Scrapers 50 consisting of inclined scraping portions 5`1`iritegr"al` withI angle arm portions 52 bolted to '93 Vand `94 on opposite sides.

"P eli the channels 41. The Iforward and rearward scraping edges 53 and 54 of the scraping flanges 44 and 45 engage a at elongated drying plate 55 which is also engaged by the lower scraping edge 56 of each corner scraper 50, the :remaining scraping `edge -57 of which scrapes the inner -surface of Seach `side wall 35 (Figure 6). The `elongated drying plate 55 is supported .on Ilongitudinally.extending .angle ymembers .58 (Figure 6) and the channels V41 are guided at their opposite ends by longitudinal angle mem- :bers 59 :and held down thereby (Figure 6). In this manl11er, the scraper units, fgenerally designated 60, which include both the plate scrapers 43 and the corner Scrapers f50 are ucaused Vto .be maintained in contact with the plate 5,5 Aduring :their v.entire pathof `travel along the plate (Figure 1).

Thelopposite yends of -each `angle member 59 are bent -llpwandlyas at 61 to facilitateentny Aandexitof the scraper units 60. Leading downwardly to the drying plate 55 from .adjacent ,the .intake conduit 24 (Figure 1) is an arcuate approach portion 62 down which the material to be dried slides, so as to enter the rearward end of the flat plate 55 and be .carried therealong by the scraper units 60. The angle members 9- carryangle brackets 63 spaced at inter- V.Vals therealong on the opposite sides thereof (Figure 1),

andthese in turn are bored to receive guide bolts or pins 64 which are secured to and depend from angle brackets 65 bolted or otherwise secured tothe side walls 35. Mounted on the bolts 64 are compression springs 66 disposed between the stationary and movable angle brackets 65 and 65, 59 respectively to yieldingly urge the scraper units 60 against the drying plate 55. Near one end, the

Aangle members 59 are pivoted at 67 to the side walls 35 `set`76 is driven by a sprocket 78 and sprocket chain 79 from a sprocket `8.0 `on theshaft -81 of an electric motor 82,the motor 82and thegear set 76 being mountedon a `base 8 3. The scrapers 43 are freed fromadhering material bya resilient .wiper84 (Figure 1) mounted on a-shaft `85 which is `resiliently urged toward the scraper unit 60 by crank arms 86 attached to tension springs 87, the .opposite endsof which are anchored as at 88 tothe sides v3 5 ofthe housing 21.

,Mounted `in a heater compartment 89 located between 4the drying `plate 55, 62 and the bottom wall 90 of the 'housing 21 (Figure 2) are multiple heating units 91 which maybe of any suitable type such as electrical, oil or .gasred, steam, hot water, infra red or the like. For steam heating units 9 1, a heating coil 92 of zigzag or undulating 'form is provided having steam intake and discharge pipes Heating units 91 may be inserted or removed as required. The bottom 90 of the .jhousing`21'is insulated by a heat-insulating layer 95. The

apparatus 20 may be broadly described as a heat-treating apparatus, `either for applying `heat or extracting it, in

Vwhich latter case the heating units 91 are replaced by con ventional refrigerating units and may be broadly described as heat-exchanging units.

The housing 21 adjacent its discharge end 29 is provided with atransverse trough 96, the rearward wall 97 'of Which extends downwardly from beneath the forward 'endof the drying plate 55, the forward wall 98 extending upward kto the forward wall 29 of the housing 2 1. The

:trough A9 6 on opposite sides is provided with inlet vand 'outlet ports 99 and A100 respectively (Figure '3) to which is connected a ight conveyor unit 101 consisting of a conduit structure, generally designated 102, having'inlet and outlet conduit portions 103 and 104 connected at Atheir lower ends respectively to the ports 99 and 100 and at their upper ends to ports 105 and 106 respectively in the side walls of a discharge hopper 107 having a downwardlyextending spout 108 with a conduit 109 leading therefrom to a means of disposal for the dried material. Pressuresealing devices 110 are inserted in each of the conduit portions 103 and 104 respectively. These pressure-sealing devices are for the purpose of sealing ott the lower sections of the conduit portions 103 and 104 when it is desired to maintain va pressure above or below atmospheric pressure in the `Vhousing 21. The details of these pressure sealing devices 110 are outside the scope of the present invention, and various types may be used, examples of which are shown in the Hapman Patents Nos. 2,559,616 of July V10, 1951, for Pressure-Sealing Apparatus for Flight Conveyors and 2,564,599 of August 14, 1951, for Self- Sealing Conveyor Construction.

Mounted within the conduit structure 102 is an endless 'ight yconveyor 1111 consisting of an endless flexible propelling member 112 such as a cable or chain on which are mounted flights 113 at intervals therealong. The flights 113 may be made of metal, rubber-like material `such as 'natural or synthetic rubber, or a combination of these materials, according to kthe .particular demands of the installation. The conveyor flights 113 of rubber-like material are :ordinarily preferred. The Hight conveyor 111 is driven by a grooveddrive wheel 114 mounted on a drive shaft 1.15 .which is driven by a motor 116 (Figure l) through sprockets 117, 118 and a sprocket chain 119, the sprocket '.118 being mounted on a worm shaft 120 driving a worm 12-1 ywhich meshes with aworm wheel 122 on the drive shaft 115. The motor 116 and gear box 123 containing the .worm gearing 121, 122 are mounted upon a common base 124 which is slidably mounted upon the hopper .-107 for tightening or loosening the ight conveyor 111, aslot 125 (Figure 3) being provided for this purpose. A drain ,pipe 126 in the lowest point of the trough 96, closed by a-Valve 127, facilitates draining or tlushing out the apparatus, and ,discharges through a door opening ln the operation of the -flat plate conveying dryer 20 show-nin-Figures ,1 to 6 inclusive, the material to be dried .isadmitted vthrough either ofthe conduits 24 or 25, depending upon .whether the material is in a wet-solid or liquid condition respectively. YHeat is of course supplied to the heatinggunits 9 1 to heat the drying plate 55 and the 4motors :82.and116 are started in operation to cause the endless conveyor chains 39 and flight conveyor 111 to travel jin their Aorbital paths. As the conveyor chains 39 are thus driven, their lower courses in traveling over the dryingplate -55 cause the scraper units 60 to engage the material coming down 'the arcuate approach portion 62 toward ltl'le drying `-plate 5 5 and propel it along the latter. As the 4wet or damp materialis moved along the goesthroughasticky condition in its transformation from .a wetto 4a-dry material is prevented from adhering to `the dryingplate'SS :and side walls 35. Furthermore, the

thickness ofthe Slayer of -material which passes over the drying plate 55 and is dried thereby is in no way dependentupon the eapabilityof'the material to adhere, as in the `case of drum dryers previously used, hence much thicker layers of material can be dried by thepresent invention than can be dried by conventional drum dryers. ,The springs 66, by urging the ,guidebars 59 downward,

apply downwardpressure to the vScrapers :43 and thereby assist in preventing adhesion of the material being dried to the drying plate 55.

When the dried material reaches the forward end of the drying plate 55, it is pushed olf the latter by the scrapers 43 and falls down the inclined side wall 97 of the trough 96 into the path of the flights 113 of the endless flight conveyor 111, being carried thereby through the conduit portion 104 (Figure 3) and pressure sealing device 110 through the port 106 in the hopper 107, falling by gravity downward through the spout 108 and conduit 109 (Figure 1). The conveyor 111, freed of the conveyed material, travels downward from the driving wheel 114 through the port 105, conduit portion 103and pressure sealing device 110 through the port 90 to the trough 96, repeating the foregoing cycle indefinitely until the apparatus is halte-d. Meanwhile, the vapors or gases resulting from the drying operation are carried away by the vent 30 located in the roof 23 of the housing 21.

Tltable flat plate dryer The tiltable Hat plate dryer, generally designated 130 (Figure 7), is, so far as its upper portions are concerned, similar to the dryer 20 shown. in Figure 1, both in construction and in general operation. Accordingly, the same reference numerals are used for corresponding parts. In the tiltable dryer 130, the rearward legs 22 are provided with brackets 131 bolted or otherwise secured thereto and having pivot pins or a pivot shaft 132 supported thereby. The latter are in turn supported by a bracket or brackets 133 rising from the oor and bolted or otherwise secured thereto.

Bolted or otherwise secured to the discharge end wall 29 of the housing 21 is a bracket 134 carrying pivot pins or trunnions 135 upon which a sleeve 136 is pivotally mounted. Bolted or otherwise secured to the floor is a bracket 137 carrying a pivot pin 138 upon which the lower end 139 of a screw shaft 140 is pivotally mounted. The upper end of the screw shaft 140 passes through the bore 141 in the sleeve 136 beneath which is mounted a hand wheel 142 having an internally-threaded hub 143 threaded upon the screw shaft 140.

The operation of the modified tiltable flat plate dryer 130 is for the most part the same as that described above in connection with the ilat plate dryer 20, except that the discharge end of the housing 21 may be raised and lowered so that liquid can be retained in a greater quantity at the intake end of the dryer. The liquid level, for example, is shown by the dotted line L in Figure 7, with the housing 21 raised at its discharge end 29. To lower the discharge end 29, the operator rotates the hand wheel 142 so as to move the hub 143 downward along the screw shaft 140, permitting the sleeve 136 and bracket 134 to move downward under the inuence of gravity. When the discharge end 39 of the housing 21 is thu lowered, the liquid level L will be altered.

Modified dryer vwith complete pressure-sealing The modified flat plate dryer, generally designated 150, shown in Figures 8, 9 and l0 is different from the flat plate dryer 20 of Figures l to 6 inclusive principally in providing completely sealed conveyors for admitting the wet material and discharging the dried material. The central or dryer portion proper, generally designated 151, of the apparatus is substantially the same in construction and operation as that shown in Figure l, and hence requires no repetition of description. Similar reference numerals designate similar portions of the apparatus. In place of the intake conduit 24 or 25 of Figure 1, the modified dryer 150 is provided with an intake or supply conveyor, generally designated 152, consisting of an approximately U- shaped conduit structure 153 including forward and return conduits 154 and 155 equipped with pressure-sealing devices 156 similar to the sealing devices 110 described above and connected to one another by a sprocket casing 157 containing a drive sprocket 158 mounted on a drive shaft 159. The latter carries a pulley of sprocket 16o which is driven by a motor (not shown) in any suitable way Mounted within the conduit system 153 is an endless ight conveyor 161 supported on the drive sprocket 158 and upon an idler sprocket 162 mounted on a shaft 163 which is journaled in an idler sprocket bearing 164. An intake or supply hopper 165 opens downward into the forward conduit portion 154 for supplying wet material thereto.

The opposite or discharge end of the machine is provided with an outlet or discharge conveyor 166 which is generally similar in construction to the supply conveyor 152 in that it has a conveyor conduit system 167 including normally-inclined forward and return conduit portions 168 and 169 provided with pressure-sealing devices 170 and a combined sprocket housing and discharge hopper 171 containing a drive sprocket 172 mounted on a drive shaft 173 having a drive pulley or sprocket 174 driven by a motor (not shown). The discharge hopper 171 is provided with a discharge conduit 175 through which the dried material is discharged into a receptacle, container or conveyor, as desired. A flight conveyor, generally designated 176, is mounted within the conduit system 167 and driven by the sprocket 172 and supported at its opposite end by an idler sprocket 177 mounted on a shaft 178 journaled in a sprocket shaft bearing 179. The flight conveyors 161 and 176 are of conventional con-l struction similar to the Hight conveyor 111 discussed above. A pipe 180 leads upward from the roof 23 of the housing 21, and is equipped with a valve 181.

The operation of the modified dryer 150 is similar to that of the dryer 20 described in connection with Figures 1 to 6 inclusive and hence requires no repetition of description. The dryer 150, however, may be operated under pressure or vacuum conditions, because the sealing devices 156 and 170 prevent entrance or escape of pressure while the material is being conveyed into or out of the apparatus.

Endless belt dryer The modified dryer, generally designated 190, shown in Figures 11 and 12 also provides continuous drying of the material but does so by carrying the material upon an endless metal belt, as described below. The dryer includes an elongated box-like housing 191 having opposite side walls 192 in which shafts 193 and 194 are journaled near the opposite end walls 195 and 196 respectively. The shaft 193 is movably mounted in slots 197 for belt slack takeup purposes. Mounted on the shafts 193 and 194 are drums 198 and 199 around which is trained an endless metal belt 200 preferably of steel or other ilexible metal. The lower course of the belt 200 is supported on rollers 201, the spindles or axles 202 of which are journaled in the opposite side walls 192 of the housing 191. The upper course of the belt 200 moves along the top of an elongated metal plate 203 having downwardly-turned opposite ends 204 and 205 and spaced apart from a lower plate 206 by end walls 207. Within the chamber 208 formed by the plates 203 and 206, the ends 207 and the side walls 192, are mounted heating units 209 containing heating coils 210 supplied with steam or other heating medium through pipes 211, in an arrangement similar to that shown at 91 in Figure 1. Mounted beneath the drum 199 at the discharge end of the belt 200 is a scraper 212 which extends across the belt and is pivotally mounted on a shaft 213 journaled in the side walls 192 of the housing 191. A crank arm 214 assisted by a tension spring 215 connected thereto at one end and to an eye 216 on the bottom wall 217 at its other end, rocks the shaft 213 and yieldingly urges the scraper 212 upwardly against the belt 200. This prevents the carrying over of material which would other-Y wise adhere to the belt 200.

In order to supply material to be dried, the upper or top wall 218 is provided with an intake or supply con-- duit 220 having ,an inclined portion 221, the ,end 222 of which vis arcuately curved for engagement by an arcuately curved damper or valve member 223. The latter is mounted .on the end of a hand lever 224 which is lyoted .at 22S upon the center of curvature of the portions 2,22 and 223 and is .provided with a handle knob 22,6 and an arcuate guide and detent member 227. A vent 228 `is ralso provided in the upper wall 218 in order to permit escape .of vapors or other gases expelled from theA material being dried.

Immediately beneath the drum 199, the bottom wall 2,17 joins .a trough 230 with opposite walls 231 and 232 respectively. An endless ight conveyor unit, generally designated `233, similar to the flight conveyor unit 101 and t,Constructed in a similar manner, has a flight conv eyor 234 traversing the trough 230 and including spaced iiights v235 mounted on an endless propelling member 236, such vas an endless cable or chain.

In the operation of the modied dryer 190, material to .be dried .is supplied to the conduit 220 and falls Athrough'the opening at the lower end 222 of the inclined ,portion 221Athereof onto the endless steel belt 200, .which is caused to travel in an orbital path by power applied to thefshaft 194. As the material is carried along by the upper course of the belt 20 (as indicated by .the .dotted lines M), the belt 200 is heated by the heating units 209 by conduction through the wall or uppervplate 203. As the material M travels from the intake conduit outlet end 222 toward the drum 199, the

liquid Vtherein is vaporized and expelled, passing outward through the .vent 228. When the material arrives above the drum 199, itis in a satisfactorily dry condition, as determined by the speed at which the belt 200 is operated and .the speed at which the material M is supplied to the conduit 220. When the dried material reaches the drum 199, it drops oif the end of the belt 200, as indicated by the dotted lines at the right-hand end of Figure A1 1, and drops down into the trough 230. From the latter, it is picked up by the ights 235 of the iiight conveyor 234 and carried to a receptacle or other container for receiving the dried material.

The modified scraper 240 shown in Figure 13 consists of a strip 241 of sheet metal, either rigid or resilient, .bolted .as at 242 to one of the ilanges of the channel member 41 and having a scraping edge 243. I f the scraper strip 241 is rigid, the resilience is provided by the resilient mounting springs 66. Y

In kthe forms of the invention employing the drying plate -55 with its arcuate approach portion 62, the members 55, 62 may be formed of stainless steel with their i Side edges welded to the sides 35 of the housing 21. This construction is especially suitable for drying food products and chemicals since no pockets exist for lodging of the material being dried and a single plate serves as the bottom and end .of the drying surface. Where the drying apparatus is of the type shown in Figure 7 with one end capable of being raised or lowered, the maximum depth of liquid to be dried out occurs at the forward or inlet end .ofthe drying plate 55 adjacent its junction with .its .arcuate approach portion 62., .as shown by the liquid level line Lin Figure 7.

What .I is:

1. A conveying heat-,treating ,apparatus comprising an elongated housing, rotatable conveyor supporting and driving elements .disposed in horizontally-spaced relationship .within said housing, a main endless exible material conveyor mounted on said elements, an elongated substantially f lat heat-exchanging table disposed adjacent said conveyor, said yconveyor having material-moving elements drivingly connected thereto and extending thereacross into engagement with said table for moving treated material therealong, elongated conveyor guide members movably mounted in said housing and engaging said conveyor, resilient elements engaging and urging said conveyor guide members and said conveyor and said material-moving elements toward and into yielding engagement with said table, a heat exchanger disposed adjacent and extending along a portion of said table, a driving motor, and driving mechanism drivingly connect- Ving said motor to one of said elements.

2. A conveying yheat-treating apparatus comprising an elongated housing, rotatable Conveyor Supporting and driving .elements disposed in horizontally-spaced relationship within said housing, a main endless flexible material conveyor mounted on said elements, an elongated substantially ilat heat-exchanging table disposed adjacent said conveyor, said .conveyor having material-moving elements drivinglyconnected thereto and extending thereacross into engagement with said table for moving treated material therealong, elongated conveyor guide members engaging said conveyor, resilient elements engaging and urging said conveyor Vguide members and said conveyor and said material-moving elements toward and into yielding ,engagement with said table, said guide members being pivotally mounted adjacent one end thereof in said housing and having their opposite ends swingable rela.- tively to the pivots thereof, a heat exchanger disposed adjacent and extending along a portion of said table, a driving motor, and driving mechanism drivingly connecting said motor to one of said elements.

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